Too late to pinch back shasta daisies? (Becky)?

I purchased two Becky variety shasta daisies at the local garden center. Each is about 2 feet high, made up of 5-6 stems and each has a leafy top and under those leaves are the beginnings of a bud. Is it too late to pinch these back? It seems too early for Becky to bloom here in Michigan. We are currently in the middle of iris season for comparison to anyone else out there. Would pinching these stems be bad for a summer bloom? I think the usual bloom time is about a month from now?